Fossil fuel is a general term for buried combustible geologic deposits of organic materials, formed from decayed plants and animals that have been converted to crude oil, coal, natural gas, or heavy oils by exposure to heat and pressure in the earth's crust over hundreds of millions of years. The utilization of fossil fuels has enabled large-scale industrial development and largely supplanted water driven mills, as well as the combustion of wood or peat for heat. Fossil fuels are a finite, non-renewable resource. When generating electricity, energy from the combustion of fossil fuels is often used to power a turbine.
Increased demand for energy by the global economy has also placed increasing pressure on the cost of fossil fuels. Aside from energy, many industries, including plastics and chemical manufacturers, rely heavily on the availability of fossil fuel derivatives as a feedstock for their manufacturing processes. Cost-effective alternatives to current sources of supply could help mitigate the upward pressure on energy and these raw material costs. Major efforts to this end are focused on the microbial production of high-energy fuels by cost-effective consolidated bioprocesses.
Fatty acids are composed of long alkyl chains and represent nature's petroleum, being a primary metabolite used by cells for both chemical and energy storage functions. These energy-rich molecules are today isolated from plant and animal oils for a diverse set of products ranging from fuels to oleochemicals. A more scalable, controllable and economic route to this important class of chemicals would be beneficial to the development of renewable energy sources.